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Servlet与Servlet容器

news 2025/6/23 3:12:54

什么是Servlet?

Servlet是Java EE（现称Jakarta EE）中的一个组件，通常用于创建动态Web内容。Servlet是运行在Web服务器上的Java程序，它处理客户端的请求并生成响应。Servlet的核心功能是处理HTTP请求和响应。下面是一个servlet例子：

@WebServlet("/example")
public class ExampleServlet extends HttpServlet {@Overridepublic void init() throws ServletException {// 初始化任务}@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// 处理GET请求response.setContentType("text/html");PrintWriter out = response.getWriter();out.println("<h1>Example Servlet</h1>");}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// 处理POST请求}@Overridepublic void destroy() {// 清理任务}
}

一个稍微完整的servlet例子：

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;@WebServlet(urlPatterns = {"/hello", "/welcome"})
public class MultiURLServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {String path = request.getServletPath();response.setContentType("text/html");PrintWriter out = response.getWriter();if ("/hello".equals(path)) {out.println("<h1>Hello, World!</h1>");} else if ("/welcome".equals(path)) {out.println("<h1>Welcome!</h1>");} else {out.println("<h1>Unknown path: " + path + "</h1>");}}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response); // For simplicity, we're handling POST the same way as GET}
}